Record 5 seconds segments of audio using MediaRecorder and then upload to the server

I want to record user's microphone 5 seconds long segments and upload each to the server. I tried using MediaRecorder and I called start() and stop() methods at 5 seconds time interval, but when I concatenate these recordings there is a "drop" sound between. So I tried to record 5 seconds segments using timeslice parameter of start() method:

navigator.mediaDevices.getUserMedia({ audio: { channelCount: 2, volume: 1.0, echoCancellation: false, noiseSuppression: false } }).then(function(stream) {
  const Recorder = new MediaRecorder(stream, { audioBitsPerSecond: 128000, mimeType: "audio/ogg; codecs=opus" });
  Recorder.start(5000); 
  Recorder.addEventListener("dataavailable", function(event) {
    const audioBlob = new Blob([event.data], { type: 'audio/ogg' });
    upload(audioBlob);
  });
});

But only the first segment is playable. What can I do, or how can I make all blobs playable? I MUST record then upload each segment. I CAN'T make an array of blobs (because the user could record 24hours of data or even more and the data needs to be uploaded on the server while the user is recording - with a 5 seconds delay).

Thank you!

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